I think A340-600 is the most beautiful civil aircraft. It is very long (75.3m), but its fuselage is very narrow (5.64m), thus looks very slim, like a women with perfect shape.

I think B747SP is the ugliest civil aircraft. It is very short, only 50m, but has very wide fuselage of B747, looks like a short and fat person. The tailfin is too large compared to the fuselage.

I agree that the A340 is a beauty, but all in all, my favorite is the 757. I think the ugliest plane is the A320 series.